syzbot

INFO: task syz.0.97:4689 blocked for more than 144 seconds.
      Not tainted 6.1.129-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.97        state:D stack:27256 pid:4689  ppid:4250   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 schedule+0xbf/0x180 kernel/sched/core.c:6636
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6695
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6b9/0xd80 kernel/locking/mutex.c:747
 exfat_sync_fs+0x67/0x100 fs/exfat/super.c:65
 sync_filesystem+0x1bc/0x220 fs/sync.c:66
 exfat_reconfigure+0x79/0xa0 fs/exfat/super.c:739
 reconfigure_super+0x43a/0x870 fs/super.c:977
 do_remount fs/namespace.c:2712 [inline]
 path_mount+0xe69/0x1090 fs/namespace.c:3378
 do_mount fs/namespace.c:3399 [inline]
 __do_sys_mount fs/namespace.c:3607 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3584
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f002cf8e90a
RSP: 002b:00007f002dd4de68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f002dd4def0 RCX: 00007f002cf8e90a
RDX: 0000400000000180 RSI: 0000400000000380 RDI: 0000000000000000
RBP: 0000400000000180 R08: 00007f002dd4def0 R09: 0000000002042023
R10: 0000000002042023 R11: 0000000000000246 R12: 0000400000000380
R13: 00007f002dd4deb0 R14: 0000000000000000 R15: 00004000000002c0
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d32e850 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d32f050 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510
2 locks held by getty/4008:
 #0: ffff88814d19a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x54a/0x1620 drivers/tty/n_tty.c:2198
3 locks held by syz.0.97/4684:
2 locks held by syz.0.97/4689:
 #0: ffff888079afa0e0 (&type->s_umount_key#55){+.+.}-{3:3}, at: do_remount fs/namespace.c:2709 [inline]
 #0: ffff888079afa0e0 (&type->s_umount_key#55){+.+.}-{3:3}, at: path_mount+0xe26/0x1090 fs/namespace.c:3378
 #1: ffff88807941c0e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_sync_fs+0x67/0x100 fs/exfat/super.c:65

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.129-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1ca/0x430 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf88/0xfd0 kernel/hung_task.c:377
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4957 Comm: kworker/u4:16 Not tainted 6.1.129-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: bat_events batadv_nc_worker
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4739 [inline]
RIP: 0010:__lock_acquire+0x642/0x1f80 kernel/locking/lockdep.c:4999
Code: 41 8b 2c 24 41 89 ec ff cd 0f 88 a2 00 00 00 89 eb 83 fd 31 73 79 48 8d 04 9b 48 8d 5c c6 20 48 89 d8 48 c1 e8 03 0f b6 04 10 <84> c0 75 18 8b 1b 41 0f b6 04 17 84 c0 75 31 41 33 1e f7 c3 00 60
RSP: 0018:ffffc9000d7779a0 EFLAGS: 00000806
RAX: 0000000000000000 RBX: ffff88802ebe0b28 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: ffff88802ebe0ae0 RDI: ffffffff912b6260
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff2256c4d
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000002
R13: ffff88802ebe0000 R14: ffff88802ebe0b50 R15: 1ffff11005d7c16a
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f368d378ab8 CR3: 000000007452a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0xe8/0x610 net/batman-adv/network-coding.c:719
 process_one_work+0x917/0x1260 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>